Discharge diffuser for screw compressor

Abstract

A discharge collector and diffuser for a screw compressor, including a housing having an inlet for receiving flow from a compressor and an outlet and defining therebetween a collector portion, a transition portion and a diffuser portion, the collector portion being adapted to receive a plurality of non-parallel streams from a compressor and to guide the streams into a substantially parallel flow direction, the housing further having a splitter plate positioned in the collector portion to separate the non-parallel streams from each other, whereby the streams are maintained separate until they are substantially parallel, thereby reducing flow losses.

1 . A discharge collector and diffuser for a screw compressor, comprising: 
 a housing having an inlet for receiving flow from a compressor and an outlet and defining therebetween a collector portion and a diffuser portion,    said collector portion being adapted to receive a plurality of non-parallel streams from a compressor, said streams having a flow profile, and said collector portion being shaped to match said flow profile and to guide said streams into a substantially parallel flow direction.    
   
   
       2 . The apparatus of  claim 1 , further comprising a splitter plate positioned in said collector portion to separate said non-parallel streams from each other, whereby said streams are maintained separate until they are substantially parallel, thereby reducing turbulence.  
   
   
       3 . The apparatus of  claim 2 , wherein a diffuser throat is defined between said collector portion and said diffuser portion, wherein said throat has a throat area (A T ) defined as follows:  
     
       

       A 
       T 
       =m/ρ 
       2 
       U,  

     
     wherein 
 m=mass flow rate,  
 ρ 2 =discharge density, and  
 U=average discharge velocity.  
 
   
   
       4 . The apparatus of  claim 1 , wherein said diffuser portion has a flow area which increases in a flow direction.  
   
   
       5 . The apparatus of  claim 1 , wherein said housing has a shroud portion adapted to communicate with both axial and radial discharge porting of said compressor.  
   
   
       6 . A screw compressor, comprising: 
 a compressor housing having a discharge port;    at least two rotors rotatably disposed in said compressor housing for generating a plurality of non-parallel streams through said discharge port, said streams having a flow profile; and    a discharge collector and diffuser comprising a collector housing having an inlet communicated with said discharge port and an outlet and defining therebetween a collector portion and a diffuser portion, said collector portion being shaped to match and flow profile and to guide said streams into a substantially parallel flow direction.    
   
   
       7 . The apparatus of  claim 6 , wherein said discharge port has axial and radial components and said collector housing has a shroud portion adapted to communicate with both of said axial and radial components.  
   
   
       8 . The apparatus of  claim 6 , wherein said discharge port and said collector housing define a collector flow passage which follows said flow profile.  
   
   
       9 . The apparatus of  claim 8 , wherein said collector flow passage decreases in cross-sectional area in a flow direction.